By Roja Cawaia LUANDA, Jan 21 (Reuters) - Pilot error caused a chartered light aircraft to crash into a mountain in Angola, killing all 13 people aboard, a senior government official said. Angolan investigators have spent two days scouring a mountaintop outside Huambo, some 450 km (280 miles) southeast of the capital Luanda, for clues to why the twin-propeller Beechcraft King Air B200 crashed early on Saturday morning. The plane went down in bad weather as it was nearing the airport in Huambo about an hour after taking off from Luanda. "A technical mistake was made by the crew of the airplane -- it was flying at under 2,000 feet in a mountainous area," Deputy Transportation Minister Helder Presa told the Jornal de Angola newspaper after visiting the crash site on Sunday. The newspaper also reported on Monday that officials would conduct a thorough technical analysis of the wreckage before issuing a report on the accident. The governor of Huambo province has confirmed that Valentim Amoes, a prominent businessman with ties to the government, was among those who died on the flight. Portugal's Lusa news agency reported on Saturday that two victims were Portuguese nationals. All were moved to a morgue in Huambo. The plane was operated by Giraglobo, a company that offers chartered flights in oil-rich Angola, which is struggling to upgrade airports, roads, bridges and other infrastructure devastated during a 27-year civil war. An economic boom, fuelled by the vast oil wealth, has led to growing demand for air travel in the country since the end of the war in 2002, straining the capacity of the state-owned TAAG airline as well smaller carriers and charter companies. A TAAG Boeing 737 crashed last year in the northern city of M'banza Congo, killing a handful of passengers and injuring dozens of others. That crash led the European Union to put TAAG on its airline blacklist. Angola's worst recent year for air accidents occurred in 2000, when two separate crashes claimed 87 lives in one month. (Writing by Paul Simao; Editing by Charles Dick)
